I only have the original Kindle Fire, so there may be changes in later generations that negate some of what I say.
I'm not that crazy about it. As an Amazon linked tool, I think they are great, but if you want an all around tablet, I would recommend getting one of the "regular" Android devices - Samsung, Lenovo, Asus, etc.
If you have the ducats to just toss out, forty bucks is a good deal if you want to play with one and you do a lot of Amazon video watching, music, etc. However, if you're thinking of also using it as a reader, don't do it. I hate mine as a reader (that includes all tablets). Your Paperwhite (I have one too) is 1000x better as a reader.